The former head of gaming website Betonsports has been freed on bail after a month in a US jail on charges of racketeering and fraud.

David Carruthers was freed on a $1m (£527,196) bail bond, which included strict curbs on his movements.

He must wear an electronic tag and has been confined to a St Louis residence.

UK-based Betonsports sacked Mr Carruthers after he was arrested by US authorities as he passed through a Texas airport on 16 July.

The group has also shut down all of its US activities since the 48-year-old's arrest. The US had been the group's biggest market.

Online gaming crackdown

The case is one of the biggest US prosecutions faced by an online gaming company.

Betonsports and executives from other gaming firms are facing a 22-count indictment alleging racketeering, fraud, tax evasion and conspiracy.

The charges allege that Betonsports failed to pay US excise taxes on more than $3.3bn in bets taken from US gamblers.

The authorities are seeking forfeiture of $4.5bn, removal of access to Betonsports sites in the US and the return of money held for US account holders.

The London-based company is currently complying with the court order by not taking bets from gamblers in the US, however it has yet to offer a defence to the US charges or have a lawyer present in court.

Analysts say the legal action is part of a bid by US authorities to make online gambling illegal in the country under the 1961 Wire Act.

The subject has been somewhat of a grey area as gambling is illegal in many parts of the US.

However, some internet gaming firms have hundreds of thousands of US customers as they are based offshore in countries that allow gambling and so were viewed as out of reach of US laws.